In 1952, England had a Great Smog that killed at least 4000 people (History.com) (The Guardian), although the history of killer smog in London dates back to the 1800s. (Guardian)

In 1966, at least 50 people were killed by a smog that covered the city of NY over Thanksgiving weekend. (Business Insider) (US Dept of Health, Education and Welfare Report from 1966)

In 1948, smog killed at least 20 people in Donora PA (a town south of Pittsburgh along the Monongahela River, north of Morgantown). (History.com) (Pittsburgh Post Gazette) (NPR)

Current smog in the western US comes from uncontrolled emissions from China (Atmospheric Chemistry and Physics), and it’s possible that one third of deaths in China come from smog. (Business Insider)

Why do we need the EPA?

Because industry will not regulate itself. Because without regulation people die.